---
title: "downsample(_:decimationFactor:filter:)"
framework: accelerate
role: symbol
role_heading: Type Method
path: "accelerate/vdsp/downsample(_:decimationfactor:filter:)-1o8it"
---

# downsample(_:decimationFactor:filter:)

Returns the downsampled double-precision vector.

## Declaration

```swift
static func downsample<T, U>(_ source: U, decimationFactor: Int, filter: T) -> [Double] where T : AccelerateBuffer, U : AccelerateBuffer, T.Element == Double, U.Element == Double
```

## Mentioned in

Resampling a signal with decimation

## See Also

### Real Vectors

- [Resampling a signal with decimation](accelerate/resampling-a-signal-with-decimation.md)
- [downsample(_:decimationFactor:filter:)](accelerate/vdsp/downsample(_:decimationfactor:filter:)-40d8o.md)
- [downsample(_:decimationFactor:filter:result:)](accelerate/vdsp/downsample(_:decimationfactor:filter:result:)-2y1iv.md)
- [downsample(_:decimationFactor:filter:result:)](accelerate/vdsp/downsample(_:decimationfactor:filter:result:)-1g4a.md)